When we apply a moisturiser, we often give little thought to what it is doing to our skin, and perhaps even less to the function of its ingredients. We know that a moisturiser should make our skin less dry, keep irritation and inflammation at bay and perhaps slow down our skin’s ageing process, but how does a moisturiser achieve these things? To understand your moisturiser, it helps to have an understanding of your skin - and what can go wrong with it.
What happens in healthy skin
Moisturisers interact only with the outermost layer of our skin, the epidermis, and more specifically the stratum corneum, which is the most superficial layer. The stratum corneum is often described as having a ‘brick and mortar’ structure, because it is made up of rows of cells called corneocytes, the ‘bricks’, that are surrounded by lipids, the ‘mortar’. The top layer of cells is shed from the stratum corneum continuously and is renewed by cells from deeper layers. Within the corneocytes are water-attracting molecules, collectively known as ‘natural moisturising factor’ that are responsible for retaining water in the stratum corneum, keeping it hydrated and elastic, and essential for the proper shedding of dead cells. The sebaceous glands shed sebum onto the surface of the stratum corneum, which adds to the lipid waterproof barrier of the skin.
Although the stratum corneum contains no living cells, it performs the life-saving function of forming a barrier to the environment. To function well and remain healthy, it must have the perfect balance of intact corneocytes that shed regularly and efficiently, the right amount of natural moisturising factor to maintain hydration and elasticity, and the correct ratio of lipids to maintain the waterproof barrier. The pH of the outer stratum corneum is acidic, between 4.5-5.3, which is important for many of the processes in the skin, including the proper formation of lipids, the shedding of corneocytes, and preventing the survival of harmful microorganisms (1).
When things go wrong with our skin
Virtually all skin problems come down to something going wrong in the stratum corneum, which is basically a failure of our skin’s barrier to function properly. Flakey, dry skin suggests a problem with the waterproof lipid layer, leading to dehydration of the stratum corneum and the irregular shedding of corneocytes. If left untreated, the damaged skin barrier can progress to redness, irritation and chronic inflammation.
Acne can be initiated by a number of different factors, but the underlying change is pore blockage. This can be caused by the abnormal shedding of corneocytes which then block the pores, production of abnormally thick sebum because of a deficiency in omega-6 fatty acids, or invasion of the pores by bacteria. Recent thinking is that acne sufferers have a compromised skin barrier because their stratum corneum is often dehydrated and loses water at a higher rate than healthy skin (2). You can read more about what happens in acne in our blog here.
What do moisturisers do?
The main purpose of moisturisers is to improve the skin’s barrier function, and their components work in different ways. The main ones are:
Emollients - these are different types of oils that improve the dry appearance of skin by filling the gaps between shedding corneocytes. They can also contribute to the lipid component of the skin’s barrier. In particular, the omega-6 fatty acids linoleic acid and gamma-linolenic acid can boost levels of ceramides in the skin (see our blog on this here). Different skin types will benefit from different types of emollients.
Occlusives - these form an impermeable layer on the skin and are designed to slow down water loss from the skin.
Humectants - these are water-attracting molecules designed to draw water onto the skin and promote hydration of the stratum corneum, effectively acting as natural moisturising factor.
Moisturisers should be chosen according to skin type - an occlusive moisturiser will cause havoc in acne-prone skin, whereas dry skin needs extra help from at least semi-occlusive ingredients. However, moisturisers are only part of the solution. The right kind of moisturiser will boost the skin’s barrier function, but should be used in conjunction with other measures that will minimise barrier damage in the first place. What’s more, it’s clear that some moisturisers contain substances that can harm the skin’s barrier.
What can damage our skin’s barrier?
Detergents
These are common causes poor skin health, because they deplete the skin of its waterproof lipid barrier. Depletion of lipids from the skin will allow water to evaporate from the skin and will also disrupt the normal shedding of corneocytes. Detergents can also deplete levels of natural moisturising factor in the stratum corneum (3), and alter the skin’s pH (1), all of which are bad news for skin health. This is why our cleansers are detergent-free - you don’t need to use detergents on your skin to keep it in the best possible health. You can read more about how our detergent-free cleansers work here.
Hot water and dry air
Hot water also depletes our skin of lipids, so we should avoid steaming hot baths and showers, and bathing time should be kept to a minimum. Air conditioning and heating can dehydrate the air, which will dehydrate our skin. Cold air holds less water and so during winter months, when we are tempted to take longer hot showers, our skin tends to be drier and more irritable.
Emulsifiers
These are detergent-like molecules added to water-containing cleansers and moisturisers. Some of these have been shown to damage the skin’s barrier, causing increased water loss from the skin (4).
What makes Mokosh moisturisers different?
Good levels of essential fatty acids
All our moisturisers are enriched for the omega-6 fatty acids linoleic acid and gamma linoleic acid. In dry skin, they will help boost ceramide levels, restoring the depleted water-proofing function. In oily and acne-prone skin, they will boost what is now known to be an omega-6 fatty acid deficiency in many cases. Replenishing omega-6 fatty acids may help to normalise the consistency of sebum so it is less likely to clog pores, and may also reduce the amount of sebum that is produced. Supplementation of acne-prone skin with omega-6 fatty acids may also play a role in preventing the abnormal shedding of corneocytes which can block the pores in acne-prone skin. This is described more fully in our blog here.
Natural plant waxes and saturated botanical oils that prevent dehydration
For drier skin types, our creams contain natural plant waxes and saturated botanical oils which can form a semi-occlusive barrier on the skin without blocking the skin’s pores. This will physically reduce evaporation of water, and will also reduce the loss of natural moisturising factor from the stratum corneum.
Emulsifier-free
Because our creams are made without water, they do not need emulsifiers. All water-containing creams require emulsifiers which are essentially detergents, and have the potential to disrupt the skin’s the lipid barrier (4).
100% certified organic botanicals
Because most moisturisers are made with around 80% water and 15-20% oils, they require the addition of a combination of synthetics that keep the blend stable - emulsifiers, preservatives and thickeners. We believe that in this type of formulation, the beneficial components are sometimes outweighed by the negatives. In contrast, our moisturisers are undiluted plant oils and butters, highly concentrated, and incredibly stable. Their naturally high levels of antioxidants, vitamins and anti-inflammatory compounds remain potent for months after opening, and they are formulated to address the important barrier problems in each skin type. The absence of synthetics means there is little chance of interference with your skin’s metabolism. Like all our products, our moisturisers are designed to work with your body, to protect and rebalance, and are made using only pure botanical ingredients. We believe this is the best approach to help your body get on with what it already knows how to do best - it will restore your skin’s natural balance and promote a return to its natural, radiant state.
References:
1) Fluhr J.W. · Elias P.M. 'Stratum corneum pH: formation and function of the ‘acid mantle’. (2002) Exog Dermatol 1:163–175
2. Thiboutot D and Del Rosso, J Q,(2013) Acne Vulgaris and the Epidermal Barrier J Clin Aesthet Dermatol. 6: 18–24
3) Fowler, J. (2012) Understanding the Role of Natural Moisturizing Factor in Skin Hydration. Practical Dermatology. July 2012.
4 ) Purnamawati, S. et al. (2017) The Role of Moisturisers in Addressing Various Kinds of Dermatitis: A Review. Clin. Med. Res. 15: 75-87
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